High-definition TV Signals Research Articles

Terahertz Heterodyne Communication Using GaAs Field-Effect Transistor Receiver

We report the first successful terahertz heterodyne communication using a field-effect transistor for detection. The communication is a real-time transmission of an uncompressed high-definition TV signal at a data rate of 1.5 Gbps with a 307-GHz carrier frequency. The emitter is a frequency-multiplied amplifier chain whose last stage is a second harmonic mixer that multiplies the carrier signal by the data. The receiver only consists of a GaAs high-electron-mobility transistor that acts as a quadratic receiver, and two 20-dB-gain amplifiers, no limiting amplifier or forward error correction were used. A direct communication would be impossible with such a combination of modulation scheme at emission and quadratic detection at reception, while it is possible in a heterodyne configuration. In addition, for the same source power, the heterodyne scheme allows to increase the communication bandwidth from 80 MHz to more than 2 GHz for a local oscillator power of −8 dBm.

60 GHz radio-over-fiber technologies for broadband wireless services [Invited

Some of the work carried out within the European integrated project Integrated Photonic mm-Wave Functions for Broadband Connectivity (IPHOBAC) on the development of photonic components and radio-over-fiber technologies for broadband wireless communication is reviewed. In detail, 60 GHz outdoor radio systems for >10 Gbits/s and 60 GHz indoor wireless systems offering >1 Gbit/s wireless transmission speeds are reported. The wireless transmission of uncompressed high-definition TV signals using the 60 GHz band is also demonstrated.

Source coding and transmission of HDTV images compressed with the wavelet transform

Digital high-definition TV (HDTV) signals are generally compressed to reduce transmission bandwidth requirements. A compression algorithm for the bit rate reduction of an HDTV image using the wavelet transform is presented. The major problems related to the transmission of a compressed HDTV signal are analyzed. Transmission is examined both on a noisy channel and an asynchronous transfer mode (ATM) network. The effects of channel noise on the reconstructed image are determined, and a solution to mitigate the degradation of the image quality is presented. A model for the output bit rate of the HDTV coder is derived and used to simulate the transmission of an ATM multiplexer so that the network's main performance parameters can be determined. >

Hierarchical coding of HDTV

The Broadband Integrated Services Digital Network (BISDN) based on lightwave technology is supposed to become the all-purpose exchange area communication network of the future. All digital services are integrated with applications ranging from facsimile, videophone, teleconferencing to digital standard-resolution TV — sometimes referred to as Extended Quality TV (EQTV) — and High Definition TV (HDTV). In order to make efficient use of the available network bandwidth hierarchical coding schemes combine the necessary data compressions of the HDTV and EQTV signals such that the HDTV signal can be transmitted at 135 Mbit/s with the embedded EQTV signal coded in a sub-channel of approximately 35 Mbit/s. This paper investigates in detail three possible coding strategies for fixed bit-rate hierarchical coding schemes, namely distributed coding, error feedback coding and selective coding. With the aid of the rate distortionn theory it is determined under which conditions both EQTV and HDTV are encoded optimally for each of the three strategies. These conditions are verified with three introduced hierarchical subband coding schemes, namely the Distributed system, the Refinement system and the Selection system, which are direct implementations of the three coding strategies. It is concluded that if both EQTV and HDTV have to be encoded optimally, the error feedback coding strategy is the best suitable one because this strategy is able to cancel propagation of coding errors of the EQTV signal into the reconstructed HDTV signal.

Multi-picture system for high resolution wide aspect ratio screen

Two novel LSI (large-scale-integrated circuit) chips for multi-picture function have been developed. These are an aspect ratio converter of IDTV (improved-definition TV) signals and a picture-in-picture processor for HDTV (high-definition TV) and NTSC signals. This IC system has achieved a multi-picture function on a wide-aspect-ratio screen.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

A coherent optical FDM CATV distribution system

A coherent optical frequency-division-multiplexing (FDM) experimental system for an optical CATV distribution service has been developed. This system employs a channel frequency spacing locked optical FDM transmitter and a random access optical heterodyne receiver. In the transmitter, ten 1.54- mu m wavelength tunable distributed-Bragg-reflector laser-diode (DBR LD) modules were FSK modulated with a 400-Mb/s PN pattern. A reference pulse method is used for channel space control. Individual channel spacings for ten LDs are stabilized to 8 GHz. The random access optical heterodyne receiver is realized with a wavelength tunable local DBR LD, polarization diversity reception technique, and random access automatic frequency controller. A current address method realizes the random access function. The results of a ten-channel FDM transmission experiment carried out to evaluate these techniques are presented. It is estimated that over 80 channel high-definition TV signals can be distributed to 2000 subscribers with 500-GHz frequency tunable DBR LD. The feasibility of expanding the subscriber number to over 10000 was confirmed by an experiment with a traveling-wave optical amplifier. >

1/2-inch cassette VTR for baseband HDTV signal recording

Technical details are reported for a 1/2-inch cassette videotape recorder (VTR) developed for recording the baseband high-definition TV (HDTV) signal. A recording time of 63 min was achieved by using metal-particle tape and laminated amorphous video heads. The frequency bandwidths used for luminance and chrominance signals were 20 and 7 MHz, respectively. A novel two-channel, three-segment recording method was developed for the purpose. Four-channel digital audio recording with a sampling frequency of 48 kHz and 16-b linear quantization was used. The digital audio signal was recorded on the overlapped area succeeding to the video track by using the same heads used for video recording. >

Wide Band Video Signal Recorder Having Level and Linearity Corrector

Extensive works are now being carried out on the development of band compression techniques for the transmission of the high definition TV (HD-TV), which would be practiced in future by utiIizing one of the channels of 12 GHz band satellite broadcastings. In this, the bandwidth of HD-TV signal which occupies the bandwidth several times that of the present system, is compressed to less than 9 MHz. By making use of the above techniques. it is desired to provide a new video signal recorder with the capability of 9 M Hz band recordings.